Combined Cytotoxic Effects of the Fungicide Azoxystrobin and Common Food-Contaminating Mycotoxins

This study assessed the cytotoxicity of the individual and combined exposure to the fungicide azoxystrobin (AZX) and the three common mycotoxins found in food: ochratoxin A (OTA), deoxynivalenol (DON), and T-2 toxin. Cytotoxic effects were evaluated using the resazurin and MTT assays in human hepatocarcinoma (HepG2) cells after 24 h of exposure, and the type of interaction between the compounds was determined using the isobologram method. Results showed that T-2 was the most cytotoxic compound, followed by DON, OTA, and AZX. The compound ratios in the mixture were calculated using three sublethal concentrations (IC_50/2, IC_50/4, and IC_50/8) to achieve equal toxicity for each compound. Interaction analysis revealed that the nature of the interaction varied across components and concentrations. The AZX and DON mixture produced an antagonistic effect at all the analyzed effect levels. AZX and OTA or T2 mixtures, and tertiary combinations displayed antagonism at low effect values but additivity at high effect levels. Importantly, the quaternary mixture demonstrated synergism at all the effect levels. These findings highlight that the co-occurrence of fungicides and mycotoxins in food commodities can lead to complex exposure scenarios that may result in combined toxic effects on the organism.